There is no bus between these two airports, so you may reserve a cab from Xiaoshan to Pudong. It takes about 2.5 hours but the cost is too much~

For an economical way, you have to transfer for several times. Firstly, take the shuttle bus or taxi to Hangzhou Railway Station. One hour is needed. Arrival on the railway station, board on a bullet train to Shanghai South Railway Station. Two hours are needed. Then, take the Pudong airport shuttle Line7 or a taxi to PVG whithin one hour. However, it is impossible to catch a train once arrive on the railway station. So, you'd better plan the journey well in advance~